Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130468
Alexandre Delécolle, R. Lima, V. V. G. Neto, J. Buisson
Independent software systems have been joined together to form alliances known as System-of-Systems (SoS). SoS are composed of constituent systems and deliver behaviors as a result of the combination of their individual functionalities. In both, single systems and SoS, the prediction of quality at design-time is of utmost importance. Among several quality attributes (QA) a SoS should cope with, availability is particularly important. Given the critical nature of several domains supported by SoS, failures and unavailability could lead to risks and losses to the SoS users. SoS are then required to be highly available. However, while the strategies to deal with availability in single systems are well-known, techniques to predict and enhance availability at SoS level while considering its inherent dynamics can be still investigated. The main contribution of this paper is the establishment of an architectural strategy at SoS level to enable a simulation-based measurement of availability at SoS architectural descriptions. Preliminary results reveal that the established strategy can be successfully used for the purpose of measurement of the QA availability in SoS architectures.
{"title":"Architectural Strategy to Enhance the Availability Quality Attribute in System-of-Systems Architectures: a Case Study","authors":"Alexandre Delécolle, R. Lima, V. V. G. Neto, J. Buisson","doi":"10.1109/SoSE50414.2020.9130468","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130468","url":null,"abstract":"Independent software systems have been joined together to form alliances known as System-of-Systems (SoS). SoS are composed of constituent systems and deliver behaviors as a result of the combination of their individual functionalities. In both, single systems and SoS, the prediction of quality at design-time is of utmost importance. Among several quality attributes (QA) a SoS should cope with, availability is particularly important. Given the critical nature of several domains supported by SoS, failures and unavailability could lead to risks and losses to the SoS users. SoS are then required to be highly available. However, while the strategies to deal with availability in single systems are well-known, techniques to predict and enhance availability at SoS level while considering its inherent dynamics can be still investigated. The main contribution of this paper is the establishment of an architectural strategy at SoS level to enable a simulation-based measurement of availability at SoS architectural descriptions. Preliminary results reveal that the established strategy can be successfully used for the purpose of measurement of the QA availability in SoS architectures.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125257485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130553
F. Oquendo
Uncertainty is intrinsically associated with the architectural design of Software-intensive Systems-of-Systems (SoS) by its very nature, e.g. in Intelligent Transportation Systems (ITS). The consequent research question is thereby how to represent uncertainty in the description of an SoS architecture and subsequently use that representation to reason about SoS architectural properties. To address this research issue in the Internet-of-Things (IoT), this paper investigates the notion of epistemic uncertainty (i.e. uncertainty due to partial knowledge) in the architectural design of IoT SoSs and proposes to enhance an existing SoS Architecture Description Language, named SosADL, with fuzzy concepts and constructs underlain by Fuzzy Theory, demonstrating its effectiveness in SoS platooning architectures of self-driving vehicles.
{"title":"Fuzzy Architecture Description for Handling Uncertainty in IoT Systems-of-Systems","authors":"F. Oquendo","doi":"10.1109/SoSE50414.2020.9130553","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130553","url":null,"abstract":"Uncertainty is intrinsically associated with the architectural design of Software-intensive Systems-of-Systems (SoS) by its very nature, e.g. in Intelligent Transportation Systems (ITS). The consequent research question is thereby how to represent uncertainty in the description of an SoS architecture and subsequently use that representation to reason about SoS architectural properties. To address this research issue in the Internet-of-Things (IoT), this paper investigates the notion of epistemic uncertainty (i.e. uncertainty due to partial knowledge) in the architectural design of IoT SoSs and proposes to enhance an existing SoS Architecture Description Language, named SosADL, with fuzzy concepts and constructs underlain by Fuzzy Theory, demonstrating its effectiveness in SoS platooning architectures of self-driving vehicles.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114564063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130552
Benjamin Weinert, M. Uslar
Within this contribution, we outline the demand and the corresponding challenges for a structured SoS (System of Systems) approach for seamless information exchange in the agriculture application domain. In order to cope with the heterogeneous infrastructure and a lack of interoperability across the agricultural domain, a reference designation based system architecture documentation approach is presented and the transfer to the agriculture domain is provided. The paper concludes with a first conceptual model for an interoperable and vendor-neutral communication framework for the agricultural domain. The outlined approach must be evaluated in further studies.
{"title":"Challenges for System of Systems in the Agriculture Application Domain","authors":"Benjamin Weinert, M. Uslar","doi":"10.1109/SoSE50414.2020.9130552","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130552","url":null,"abstract":"Within this contribution, we outline the demand and the corresponding challenges for a structured SoS (System of Systems) approach for seamless information exchange in the agriculture application domain. In order to cope with the heterogeneous infrastructure and a lack of interoperability across the agricultural domain, a reference designation based system architecture documentation approach is presented and the transfer to the agriculture domain is provided. The paper concludes with a first conceptual model for an interoperable and vendor-neutral communication framework for the agricultural domain. The outlined approach must be evaluated in further studies.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114754467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130509
Moritz Wäschle, Yi Jiang, M. Behrendt, A. Albers
Transport networking (also Vehicle-to-Everything (V2X)) can be regarded as a System of Systems (SoS). For validation purposes, the specific properties of the SoS must be taken into account. This paper proposes the adaption of methods from modular kit development and systems engineering to fit the SoS characteristics. From this, a concept of a mixed physical-virtual validation environment can be derived to support the validation of V2X. Due to its modular and distributed character, the environment allows for quick adaptations. The principle functionality of the concept was verified using a green wave maneuver in a Vehicle-to-Infrastructure application.
{"title":"Development of an integrated validation environment for System of Systems in the context of V2X using the XiL-Approach","authors":"Moritz Wäschle, Yi Jiang, M. Behrendt, A. Albers","doi":"10.1109/SoSE50414.2020.9130509","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130509","url":null,"abstract":"Transport networking (also Vehicle-to-Everything (V2X)) can be regarded as a System of Systems (SoS). For validation purposes, the specific properties of the SoS must be taken into account. This paper proposes the adaption of methods from modular kit development and systems engineering to fit the SoS characteristics. From this, a concept of a mixed physical-virtual validation environment can be derived to support the validation of V2X. Due to its modular and distributed character, the environment allows for quick adaptations. The principle functionality of the concept was verified using a green wave maneuver in a Vehicle-to-Infrastructure application.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"197 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115647464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130543
Hemza Redjimi, J. Tar
In this paper a system of cooperating robots manipulating a rigid object is considered. The robots are constructed of redundant open kinematics chains containing prismatic and rotary joints, and may have different, general structures. For solving the inverse kinematic task of such structures generally only differential approaches are applicable that may cope with problems in the unavoidable kinematic singularities. In the present approach the “master” robot can rigidly grip the workpiece and moves it accordingly. The cooperating ones (the “slaves”) can grip the same workpiece with grippers provided with“elastic adapters” that can be deformed if they execute their motion nearby their kinematic singularities where the tracking precision of the construction is limited. A general differential solution is provided for the inverse kinematic task that is based on the Moore-Penrose pseudoinverse with a tracking errordependent damping factor. Simulation results are presented for two cooperating 8 Degree of Freedom robot arms to exemplify the simplicity of the suggested method.
{"title":"Flexible Solution of the Inverse Kinematic Task for Cooperating Robots of Different Structures","authors":"Hemza Redjimi, J. Tar","doi":"10.1109/SoSE50414.2020.9130543","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130543","url":null,"abstract":"In this paper a system of cooperating robots manipulating a rigid object is considered. The robots are constructed of redundant open kinematics chains containing prismatic and rotary joints, and may have different, general structures. For solving the inverse kinematic task of such structures generally only differential approaches are applicable that may cope with problems in the unavoidable kinematic singularities. In the present approach the “master” robot can rigidly grip the workpiece and moves it accordingly. The cooperating ones (the “slaves”) can grip the same workpiece with grippers provided with“elastic adapters” that can be deformed if they execute their motion nearby their kinematic singularities where the tracking precision of the construction is limited. A general differential solution is provided for the inverse kinematic task that is based on the Moore-Penrose pseudoinverse with a tracking errordependent damping factor. Simulation results are presented for two cooperating 8 Degree of Freedom robot arms to exemplify the simplicity of the suggested method.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128858661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130529
S. Kokkula, G. Muller, Elisabet Syverud, K. Falk
The paper summarizes the challenges and experiences from a course in research methods for systems engineering master’s students. This course is a preparatory course for the final master’s project. Each student selects a topic to investigate in the course. Most of these topics fall into the category of systems of systems engineering. This paper investigates the underlying course contents, teaching method, evaluation, and feedback to/from students. We learnt/noticed that students had challenges in writing the research questions and framing the research design. To overcome these challenges, we demonstrate a systematic procedure by offering a “research framework”.
{"title":"Experiences from Teaching Master level Course in Research Methods in Systems of Systems Engineering","authors":"S. Kokkula, G. Muller, Elisabet Syverud, K. Falk","doi":"10.1109/SoSE50414.2020.9130529","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130529","url":null,"abstract":"The paper summarizes the challenges and experiences from a course in research methods for systems engineering master’s students. This course is a preparatory course for the final master’s project. Each student selects a topic to investigate in the course. Most of these topics fall into the category of systems of systems engineering. This paper investigates the underlying course contents, teaching method, evaluation, and feedback to/from students. We learnt/noticed that students had challenges in writing the research questions and framing the research design. To overcome these challenges, we demonstrate a systematic procedure by offering a “research framework”.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"2017 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127561151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130482
Mehrdad Kazerani, K. Tehrani
This paper portrays the concept of Grid of Hybrid AC/DC Microgrids, as a new paradigm for smart cities of future. The focus is on the challenges faced and advantages expected in the seemingly inevitable shift from the existing traditional supply-demand model (characterized by centralized remote bulk power generation, long transmission lines, unidirectional power flow at distribution level from the producer (grid) to consumer (customer), irresponsive loads, separate energy carriers, and low penetration of renewable energy sources) to the new pattern (characterized by distributed generation close to the point of use, bidirectional power flow in distribution feeders, controllable/responsive loads such as plugin electric vehicle chargers, thermal loads and air conditioning systems, integrated energy carriers, and very high penetration of renewable energy sources). The energy system architecture envisioned in this paper is applicable to both existing cities and new cities still in planning stage, and is expected to result in more customer control, higher reliability and sustainability, higher power quality and efficiency, cleaner environment and lower energy cost.
{"title":"Grid of Hybrid AC/DC Microgrids: A New Paradigm for Smart City of Tomorrow","authors":"Mehrdad Kazerani, K. Tehrani","doi":"10.1109/SoSE50414.2020.9130482","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130482","url":null,"abstract":"This paper portrays the concept of Grid of Hybrid AC/DC Microgrids, as a new paradigm for smart cities of future. The focus is on the challenges faced and advantages expected in the seemingly inevitable shift from the existing traditional supply-demand model (characterized by centralized remote bulk power generation, long transmission lines, unidirectional power flow at distribution level from the producer (grid) to consumer (customer), irresponsive loads, separate energy carriers, and low penetration of renewable energy sources) to the new pattern (characterized by distributed generation close to the point of use, bidirectional power flow in distribution feeders, controllable/responsive loads such as plugin electric vehicle chargers, thermal loads and air conditioning systems, integrated energy carriers, and very high penetration of renewable energy sources). The energy system architecture envisioned in this paper is applicable to both existing cities and new cities still in planning stage, and is expected to result in more customer control, higher reliability and sustainability, higher power quality and efficiency, cleaner environment and lower energy cost.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124465312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130544
J. Shao, Minghao Li, Kewei Yang
Unmanned aerial vehicle (UAV) swarm, as a large-scale integrated system, has been widely used in civil and military fields. Building a model of a drone swarm and assessing the system capabilities is a challenging task. In this paper, a multi-layer network modeling method, considering the indicator, logic and collaboration of the constituent systems (CSs), is proposed to build the architecture of the UAV swarm system. On this basis, the generation processes of system-level capabilities in multi-layer networks are studied. Finally, we take the UAV swarm system as a case to illustrate the calculation process and results of the proposed model. It shows that the multi-layer network model can effectively assist the system-level capability generation of the UAV swarm, and the network structure can have both positive and negative effects on the system.
{"title":"Multi-layer Modeling for Capability Generation of UAV Swarm System","authors":"J. Shao, Minghao Li, Kewei Yang","doi":"10.1109/SoSE50414.2020.9130544","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130544","url":null,"abstract":"Unmanned aerial vehicle (UAV) swarm, as a large-scale integrated system, has been widely used in civil and military fields. Building a model of a drone swarm and assessing the system capabilities is a challenging task. In this paper, a multi-layer network modeling method, considering the indicator, logic and collaboration of the constituent systems (CSs), is proposed to build the architecture of the UAV swarm system. On this basis, the generation processes of system-level capabilities in multi-layer networks are studied. Finally, we take the UAV swarm system as a case to illustrate the calculation process and results of the proposed model. It shows that the multi-layer network model can effectively assist the system-level capability generation of the UAV swarm, and the network structure can have both positive and negative effects on the system.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121540682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130531
M. J. Songhori, L. V. Dongen, M. Rajabalinejad
Socio-technical systems are highly complex in which a number of domains each of which including numerous interdependent elements are present. Therefore, for adaptation of sociotechnical systems, Part 1 of this paper presented a multi-domain approach based upon Design Structure and Multi-domain matrices to develop/analyze a multi-domain model of those system. Moreover, that model is analyzed according to both (1) the change propagation measures of the non-human domain and (2) the information processing view of the stakeholder domain of the socio-technical system. This papers presents application of the presented method in the Dutch railway system. We have reviewed the relevant railway literature, and interviewed with a number of the Dutch railway experts and validated our model. The results are presented in this paper.
{"title":"A Multi-domain Approach Toward Adaptations of Socio-technical Systems: The Dutch Railway Case-Part 2","authors":"M. J. Songhori, L. V. Dongen, M. Rajabalinejad","doi":"10.1109/SoSE50414.2020.9130531","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130531","url":null,"abstract":"Socio-technical systems are highly complex in which a number of domains each of which including numerous interdependent elements are present. Therefore, for adaptation of sociotechnical systems, Part 1 of this paper presented a multi-domain approach based upon Design Structure and Multi-domain matrices to develop/analyze a multi-domain model of those system. Moreover, that model is analyzed according to both (1) the change propagation measures of the non-human domain and (2) the information processing view of the stakeholder domain of the socio-technical system. This papers presents application of the presented method in the Dutch railway system. We have reviewed the relevant railway literature, and interviewed with a number of the Dutch railway experts and validated our model. The results are presented in this paper.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127969775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/SoSE50414.2020.9130537
Michael DeMoor, John J. Prevost
Computer Vision is a valuable tool that can be used to enhance the components of many working systems. In particular, many applications can be improved by incorporating instance segmentation into their designs to help better process visual information in the surrounding environment. However, instance segmentation algorithms have traditionally been too slow to be used by any real-time systems that could benefit from using them. This includes examples such as self-driving vehicles or autonomous drones. In this work we provide an overview of the shortcomings for current instance segmentation algorithms, introduce an ongoing effort to create a new one that achieves ultrafast speeds without sacrificing competitive accuracy, and explain the advantages of employing an ultra-fast real-time version of one as a component in different systems.
{"title":"Improving Applications of Systems of Systems using Ultra Fast Instance Segmentation","authors":"Michael DeMoor, John J. Prevost","doi":"10.1109/SoSE50414.2020.9130537","DOIUrl":"https://doi.org/10.1109/SoSE50414.2020.9130537","url":null,"abstract":"Computer Vision is a valuable tool that can be used to enhance the components of many working systems. In particular, many applications can be improved by incorporating instance segmentation into their designs to help better process visual information in the surrounding environment. However, instance segmentation algorithms have traditionally been too slow to be used by any real-time systems that could benefit from using them. This includes examples such as self-driving vehicles or autonomous drones. In this work we provide an overview of the shortcomings for current instance segmentation algorithms, introduce an ongoing effort to create a new one that achieves ultrafast speeds without sacrificing competitive accuracy, and explain the advantages of employing an ultra-fast real-time version of one as a component in different systems.","PeriodicalId":121664,"journal":{"name":"2020 IEEE 15th International Conference of System of Systems Engineering (SoSE)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134471149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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